Electrical and Arc

8/10/2019 Electrical and Arc

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University of Louisville

Physical Plant Department

Electrical & Arc FlashSafety Program

2007


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Introduction

Electricity is a serious workplace hazard, capable of causing both employee injury andproperty damage. It is the policy of University of Louisville, Physical Plant Departmentto protect all employees, students, and other personnel from potential electricalhazards. This will be accomplished through compliance with the work practicesdescribed in this policy along with effective application of engineering controls,administrative controls, and the use of personal protective equipment.

This Electrical & Arc Flash Safety Program is founded on the principle of avoidingenergized work unless it is absolutely necessary. Live parts will be de-energized beforean employee works on or near them unless one of the conditions applies:

De-energizing introduces additional or increased hazards. Examples ofadditional or increased hazards would include deactivation of emergency alarmsystems or shutdown of hazardous location ventilation systems.

De-energizing is not possible due to equipment design or operational limitations.Examples of this situation would include testing and troubleshooting of electricalcircuits that can only be performed with the circuit energized and work on circuitsthat form an integral part of a continuous process that would otherwise need tobe completely shut down in order to permit work on one circuit or piece ofequipment.

Live parts are operating at less than 50 volts to ground and there is no increasedexposure to electrical burns or to explosion due to electrical arcs.

PURPOSE

This program has been established in order to:

Ensure the safety of employees who may work on or near electrical systems.

Ensure that employees understand and comply with safety standards related toelectrical safety.

Ensure that employees follow uniform practices during the completion ofelectrical work.


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RESPONSIBLITIES

Physical Plant Department

Assist shops in implementing the provisions of this program.

Provide or assist in task specific training for electrical work qualifications.

Periodically review and update this written program.

Provide or coordinate general training for shops on the content of this program.

Evaluate overall effectiveness of the Electrical & Arc Flash Safety Program on aperiodic basis.

Supervisors/ Shop Foremen

Determine the applicability of the Electrical & Arc Flash Safety Program toactivities conducted within their respective areas.

Responsible for the implementation of the Electrical & Arc Flash Safety Programwithin their areas.

Ensure employees comply with all provisions of the Electrical & Arc Flash SafetyProgram.

Ensure employees receive training appropriate to their assigned electrical tasksand maintain documentation of such training.

Develop and maintain a listing of all qualified employees in their areas.

Ensure employees are provided with and use appropriate protective equipment.

Employees

Follow the work practices described in this document, including the use ofappropriate protective equipment and tools.

Attend all training required relative to this program.

Immediately report any concerns related to electrical safety to supervision.


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DEFINITIONS

The following terms are defined in order to allow a better understanding of this program.

Arc rating: The maximum incident energy resistance demonstrated by amaterial (or a layered system of materials) prior to breaking open or at theonset of a second-degree skin burn. This rating is assigned to electricalprotective clothing and is normally expressed in calories per square centimeter(cal/cm2).

Electrically safe work condition: A state in which the conductor or circuit partto be worked on or near has been disconnected from energized parts,locked/tagged in accordance with U of L Physical Plant policy, tested to ensurethe absence of voltage, and grounded if determined necessary.

Energized: Electrically connected to or having a source of voltage.

Exposed (as applied to live parts): Capable of being inadvertently touched orsuitably guarded, isolated, or insulated.

Flash hazard analysis: A study to investigate a workers potential exposure toarc-flash energy, conducted for the purpose of injury prevention and thedetermination of safe work practices along with appropriate levels of PPE.

Flash protection boundary: An approach limit at a distance from exposed liveparts within which a person could receive a second-degree burn if an electricalarc flash were to occur.

Flash suit: A complete FR clothing and equipment system that covers the entirebody, except for the hands and feet. (Such a suit typically includes pants, jacket,and a bee-keeper style hood fitted with a face shield).

FR apparel: Flame-resistant apparel; describes a broad category of clothingdesigned to protect employees from electrical arc events during completion ofenergized tasks.

Incident energy: The amount of energy impressed on a surface, a certaindistance from the source, generated during an electrical arc event. One of the


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units used to measure incident energy is calories per square centimeter(cal/cm

2).

Limited approach boundary: An approach limit at a distance from an exposedlive part within which a shock hazard exists.

Live parts: Energized conductive components.

Prohibited approach boundary: An approach limit at a distance from anexposed live part within which work is considered the same as making contactwith the live part.

PPE: An acronym for Personal Protective Equipment.

Qualified person: One who has skills and knowledge related to the constructionand operation of the electrical equipment and installation and has receivedtraining on the hazards involved.

Restricted approach boundary: An approach limit at a distance from anexposed live part within which there is an increased risk of shock (due toelectrical arc-over combined with inadvertent movement) for personnel working inclose proximity to the live part.

Unqualified person: Any person who does not meet the definition of a qualifiedperson.

Working near (live parts): Any activity within a Limited Approach Boundary.

Working on (live parts): Coming in contact with live parts via tools, probes, testequipment, hands, feet, or other body parts regardless of the level of PPE worn.

TRAINING

Employees who are exposed to an electrical hazard that is not reduced to a safelevel by the installation must be trained.

The level of electrical safety training provided is dependent on whether theemployee is classified as a qualified person or unqualified person.

A qualified person shall be trained and knowledgeable in all of the followingtopics:

o Construction and operation of equipment on which work is assigned.

o Skills and techniques necessary to distinguish exposed energized parts fromother parts of electrical equipment.


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o Skills and techniques necessary to determine the nominal voltage of exposed

live parts.

o The approach distances specified in this document and the corresponding

voltages to which the qualified employee will be exposed.

o The process necessary to determine the degree and extent of electricalhazards along with the PPE and job planning necessary to perform the tasksafely.

A person can be considered qualified with respect to certain equipment andmethods but unqualified for others.

An unqualified person shall be trained in the inherent hazards of electricity and

any related work practices that are necessary for their safety.

Training must be provided before the employee is assigned duties that involvework near or on electrical systems.

Each supervisor and the Manager of Safety & Staff Development shall maintain arecord of all electrical training provided to their employees along with a listing ofall employees classified as qualified persons.

WORKING ON OR NEAR LIVE PARTS

Energized electrical work under 600 volts does not require a work permitif theemployee performing the work follows the guidelines in this program (e.g. wears Indurawork uniform and cotton undershirt, uses appropriate PPE, etc.). Reference NationalFire Protection Associations standard NFPA 70E.

Energized Electrical Work Permit Energizedwo rk over 600 vol ts

If live parts are not placed in an electrically safe condition, work to be performedshall be considered energized electrical work and will be performed by writtenpermit only.

A copy of the U of L Physical Plant Energized Electrical Work Permit can befound in Appendix A of this document. The intent of this permit is to ensure thatall appropriate safety precautions are taken prior to starting energized electricalwork.

Work related to testing, troubleshooting, and voltage measuring may becompleted without a permit provided appropriate safe work practices and PPEare used.


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The permit is to be originated by the individual requesting that the energizedwork be completed. (This will normally be the supervisor of the employee whowill be completing the work).

All Energized Electrical Work Permits should be submitted to the ElectricalSuperintendent or his/her designee and/or Manager of Safety for approval.

The permit must be posted in the area where the energized work is taking placefor the duration of the task.

Energized electrical work permits must be kept on file by the supervisor uponcompletion of the task.

Approach Boundaries to Live Parts

Observing a safe approach distance from exposed energized parts is an effectivemeans of maintaining electrical safety. As the distance between an individualand live parts increases, the potential for an electrical injury decreases.

Safe approach distances will be determined for all tasks in which approachingpersonnel are exposed to live parts.

Safe approach distances to fixed live parts can be determined by referring toAppendix B, Approach Boundaries to Live Parts for Shock Protection. Thisappendix can be used to identify the Limited, Restricted, and Prohibited

Approach Boundaries associated with various system voltages.

Unqualified persons may only cross the Limited Approach Boundary when theyare under the direct supervision of a qualified person.

Qualified persons may not cross or take any conductive object closer than theRestricted Approach Boundary unless one of the following conditions apply:

o The qualified person is insulated or guarded from the live parts and no un-insulated part of the qualified persons body crosses the Prohibited

Approach Boundary.

o The live parts are insulated from the qualified person and from any otherconductive object at a different potential.


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Crossing the Prohibited Approach Boundary is considered the same as makingcontact with energized parts. Qualified persons may only cross this boundarywhen all of the following precautions have been taken:

o The qualified person has specific training to work on energized parts.

o The qualified person uses PPE appropriate for working on energizedparts, which are rated for the voltage and energy level involved.

Other Precautions for Personnel Activities

Employees shall not reach blindly into areas that might contain exposed liveparts.

Employees shall not enter spaces containing live parts unless illumination isprovided that allows the work to be performed safely.

Conductive articles of jewelry and clothing (such as watchbands, bracelets, rings,key chains, necklaces, metalized aprons, cloth with conductive thread, metalheadgear, or metal frame glasses) shall not be worn where they present anelectrical contact hazard with exposed live parts. University of Louisville masterkeys must be removed and placed in a secure location.

Conductive materials, tools, and equipment that are in contact with any part of anemployees body shall be handled in a manner that prevents accidental contactwith live parts. Such materials and equipment include, but are not limited to, longconductive objects such as ducts, pipes, tubes, conductive hose and rope, metal-

lined rules and scales, steel tapes, pulling lines, metal scaffold parts, structuralmembers, and chains.

When an employee works in a confined space or enclosed space (such as amanhole or vault) that contains exposed live parts, the employee shall obtain aConfined Space Work Permit and use protective shields, barriers, or insulatingmaterials as necessary to avoid contact with these parts. Doors, hinged panels,and the like shall be secured to prevent them from swinging into employees.

PERSONAL PROTECTIVE EQUIPMENT

General Requirements

Employees working in areas where electrical hazards are present shall beprovided with, and shall use, protective equipment (Arc Flash Gear) that isdesigned and constructed for the specific body part to be protected and for thework to be performed.


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U of L Physical Plant will provide electrical protective equipment (Arc Flash Gear)required by this program at no cost to employees. Such equipment shall includean Arc Flash rated apparel, eye protection, head protection, hand protection,insulated footwear, and face shields where necessary. U of L Physical Plant isnot responsible for providing under layers of clothing.

All protective equipment shall be maintained in a safe, reliable condition by theemployee to whom it is issued.

Employees shall wear nonconductive head protection whenever there is adanger of a head injury from electric shock or burns due to contact with live partsor from flying objects resulting from an electrical explosion.

Employees shall wear nonconductive protection for the face, neck, and chinwhenever there is danger of injury from exposure to electric arcs or flashes orfrom flying objects resulting from an electrical explosion.

Employees shall wear protective equipment for the eyes and face wheneverthere is a danger of injury from electric arcs, flashes, or from flying objectsresulting from an electrical explosion.

Employees shall wear rubber-insulating gloves where there is a danger of handand arm injury due to contact with live parts or possible exposure to arc flashburn.

If an employee is wearing shoes other than hard-soled type (tennis shoes are notconsidered hard soled), he/she must wear dielectric overshoes, which will beprovided by the Physical Plant.

Face shields without an arc rating will not be used for electrical work. Safetyglasses or goggles must always be worn underneath face shields.

Additional illumination may be needed when using tinted face shields asprotection during electrical work.

Flash Protection Boundary

Personal protective equipment shall be provided to and used by all employeesworking within the Flash Protection Boundary.

For systems that are 600 volts or less the Flash Protection Boundary shall be aminimum of four feet. The formula in Appendix C can be used to determine theexact Flash Protection Boundary for systems over 600 volts.

For systems that are above 600 volts, the Flash Protection Boundary shall bedetermined through engineering analysis.


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The specific protective equipment to be worn within the Flash ProtectionBoundary can be determined by either of the following two methods:

o Complete a flash hazard analysis that determines the incident exposureenergy of each employee. Appropriate protective clothing can then be

selected based on the calculated exposure level.

o Determine the hazard level of the task by referring to NFPA 70E Table130.7 (C) (9) (a), Hazard/Risk Category Classifications (Appendix D ofthis document). This table also indicates whether voltage-rated glovesand/or tools need to be used. Once the hazard level of the task has beendetermined, the required PPE can then be ascertained from NFPA 70ETable 130.7 (C) (10), Protective Clothing and PPE Matrix. (Appendix Eof this document).

o U of L Physical Plant Shops shall develop and maintain a listing of the

specific PPE requirements for each energized electrical task conducted bytheir employees using the form found in Appendix F of this document.

Flame-Resistant Apparel & Under Layers

FR apparel shall be visually inspected before each use. FR apparel that is

contaminated or damaged shall not be used. Protective items that becomecontaminated with grease, oil, flammable liquids, or combustible liquids shall notbe used.

The garment manufacturers instructions for care and maintenance of FR apparelshall be followed.

When FR apparel is worn to protect an employee, it shall cover all ignitableclothing and allow for movement and visibility.

FR apparel must cover potentially exposed areas as completely as possible. FR

shirtsleeves must be fastened and FR shirts/jackets must be closed at the neck.

Non-melting, flammable garments (i.e. cotton, wool, rayon, silk, or blends ofthese materials) may be used as under layers beneath FR apparel.

Meltable fibers such as acetate, nylon, polyester, polypropylene, and spandexshall not be permitted in fabric under layers next to the skin. (An incidental


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amount of elastic used on non-melting fabric underwear or sock shall bepermitted).

FR garments worn as outer layers over FR apparel (i.e. jackets or rainwear) mustalso be made from FR material.

Flash suits must permit easy and rapid removal by the user.

Rubber Insulating Equipment

Rubber insulating equipment includes protective devices such as gloves,sleeves, blankets, and matting.

Insulating equipment must be inspected for damage before each days use andimmediately following any incident that could have caused damage.

An air test must be performed on rubber insulating gloves before each use.

Insulating equipment found to have defects that might affect its insulatingproperties must be removed from service until testing indicates that it isacceptable for continued use.

Where the insulating capability of protective equipment is subject to damageduring the use, the insulating material shall be protected by an outer covering ofleather or other appropriate material.

Rubber insulating equipment must be tested according to the schedule containedin Appendix G.

Rubber insulating equipment must be stored in an area protected from light,temperature extremes, excessive humidity, ozone, and other substances andconditions that may cause damage.

Insulated Tools and Materials

Only insulated tools and equipment shall be used within the Limited ApproachBoundary of exposed energized parts.

Insulated tools shall be rated for the voltages on which they are used.

Insulated tools shall be designed and constructed for the environment to whichthey are exposed and the manner in which they are used.

Insulated tools shall be protected from damage and degradation of the integrity ofthe insulation.


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Fuse or fuse holder handling equipment, insulated for the circuit voltage, shall beused to remove or install a fuse if the fuse terminals are energized.

Ropes and hand lines used near exposed energized parts shall benonconductive.

Portable ladders used for electrical work shall have nonconductive side rails.

ALERTING TECHNIQUES

Barricades shall be used in conjunction with safety signs to prevent or limitaccess to work areas containing live parts. Conductive barricades shall not beused where they might cause an electrical hazard. Barricades shall be placed nocloser than the Limited Approach Boundary.

Barricades, such as plastic fencing, must be in place if workers have to leave

energized parts exposed over 600 volts.

If signs and barricades do not provide sufficient protection, and attendant will beassigned to warn and protect pedestrians. The primary duty of the attendantshall be to keep unqualified persons out of the work area where an electricalhazard exists. The attendant shall remain in the area as long as there is apotential exposure to electrical hazards.

CONTRACT EMPLOYEES

Safety programs used by contractors on U of L Physical Plant jobsites must meetor exceed all applicable guidelines of this Safety Program.

Contractors will be required to comply with applicable Safety and Healthregulations such as OSHA, NFPA, EPA, etc.

Contractors may be required to submit copies of their Safety Program to U of LPhysical Plant upon request.


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c. Voltage above 600-category 4 arc flash coat, pants high voltage gloves,switching hood and earplugs.


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Appendix A: Energized Electrical Work Permit

(Required for work over 600 volts only)Part 1: To be completed by the requestor or supervisor of the job

Description of Circuit & Equipment: Job Location:

Description of Work to be Done:

Justification of why the circuit cannot be de-energized or the work delayed until the next

scheduled outage:

Part 2: To be completed by the qualified person(s) completing the work

(1)Detailed description of procedure to be used in performing the above work:

(2)Description of safe work practice to be employed:

(3)Voltage exposure (shock hazard analysis):

(4)Determination of shock protection boundaries:

(5)Results of flash hazard analysis:

(6)Determination of flash protection boundaries:

(7)PPE required to safely perform the task:

(8)Method used to restrict access to the work area:

(9)Do you agree the above work can be done safely? YES (proceed to Part 3)NO (return to requestor)

Qualified Person: _________________________ Date: ____________________



Part 3: To be completed by SupervisorApprovals:

Name Job Title Date

______________________________________________________________________________________________________________________________________________

_______________________________________________________________________

Note: A supervisor must approve all energized work before starting.


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Appendix B:Approach Boundaries to Live Parts for Shock Protection

(All dimensions are distance from live part to employee)

NominalSystemVoltage

(phase tophase)

LimitedApproachBoundary

(fixed circuitparts)

RestrictedApproach Boundary

(includesinadvertent

movement adder)

ProhibitedApproachBoundary

Less than 50V Not specified Not specified Not specified

50V to 300V 3 feet, 6 inches Avoid contact Avoid Contact

301V to 750V 3 feet, 6 inches 1 foot 1 inch

751V to 15 kV 5 feet 2 feet, 2 inches 7 inches

Over 15 kV ormovableconductor

See NFPA 70 E Table 130.2 (C)

Limited Approach Boundary: Distance from an exposed live part within whicha shock hazard exists. An unqualified person may not cross this boundaryunless they are continuously escorted by a qualified person.

Restricted Approach Boundary: Distance from an exposed live part withinwhich there is an increased risk of shock (due to electrical arc-over combinedwith inadvertent movement) for personnel working in close proximity to the live

part. This boundary may only be crossed by a qualified person who is safelyinsulated or guarded from the live parts.

Prohibited Approach Boundary: Distance from an exposed live part withinwhich work is considered the same as making contact with the live part. Thisboundary may only be crossed by a qualified person who has specific training towork on energized parts; has obtained an approved Energized Electrical WorkPermit; and uses PPE appropriate for working on energized parts which are ratedfor the voltage and energy level involved. (Note: A permit is not required forwork related to testing, troubleshooting, and voltage measuring).

Flash Protection Boundary (not listed in table): Distance from exposed liveparts within which a person could receive a second-degree burn if an electricalarc flash were to occur. This boundary may only be crossed by a qualifiedperson wearing the appropriate PPE. For systems that are 600 volts or less, theFlash Protection Boundary shall be a minimum of four feet. An analysis must beperformed to determine the Flash Protection Boundary for systems that areabove 600 volts.


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Appendix C:Formula for Calculation of Flash Protection Boundary

Dc= [2.65 x MVAbfx t]

OR

Dc= [53 x MVA x t]

Where:

Dc= Distance in feet from an arc source for a second-degree burn

MVAbf= Bolted fault capacity available at point involved (in mega volt-amps)

MVA= Capacity rating of transformer (mega volt-amps). For transformers with MVAratings below 0.75 MVA, multiply the transformer MVA rating by 1.25

t= Time of arc exposure (in seconds)

Examples:

1. Transformer 1000kVA = 1.0 mVA, and breaker trip setting instantaneous of 0.1seconds

Dc= [53 x 1 x 0.1]

Dc= (5.3)

Dc= 2.3 feet

2. Transformer 1000kVA = 1.0mVA, and breaker trip setting at short time delay of0.5 seconds

Dc= [53 x 1 x 0.5]

Dc= (26.5)

Dc= 5.1 feet

Flash Protection Boundary increases with breaker trip settings.


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Appendix D: Hazard/Risk Category Classifications

Task (Assumes equipment isenergized, and work is donewithin the Flash Protection

Boundary)

Hazard/RiskCategory

V-ratedGloves

V-ratedTools

Panelboards Rated 240 V and Below

Circuit breaker (CB) or fusedswitch operation with covers on

0 N N

CB or fused switch operation withcovers off

0 N N

Work on energized parts,including voltage testing

1 Y Y

Remove/install CBs or fusedswitches

1 Y Y

Removal of bolted covers (to

expose bare, energized parts)

1 N N

Opening hinged covers (toexpose bare, energized parts)

0 N N

Panelboards or Switchboards Rated > 240 V and up to 600 V (with molded caseor insulated case circuit breakers)

CB or fused switch operationwith covers on

0 N N

CB or fused switch operation withcovers off

1 N N

Work on energized parts,including voltage testing

2 (*) Y Y

PPE Requirements can be found in Appendix E

Additional Information:

V-rated Gloves are gloves rated and tested for the maximum line-to-line voltageupon which work will be done.

V-rated Tools are tools that are rated and tested for the maximum line-to-linevoltage upon which work will be done.

2(*) means that a double-layer switching hood and hearing protection arerequired for this task in addition to the other Hazard/Risk Category requirements

of Appendix E. Y = Yes (required)

N = No (not required)

Notes:

25kA short circuit current available, 0.03 second (2 cycle) fault clearing time.

For


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Appendix E: Personal Protective Equipment Matrix

Protective Clothing andEquipment

Protective Systems for Hazard/Risk Category

Hazard/Risk Category Number -1(3) 0 1 2 3 4

Non-melting (according to ASTM F 1506-00) or Untreated Natural Fibera. T-shirt (short-sleeve) X X X X

b. Shirt (long-sleeve) X

c. Pants (long) X X X(4) X(6) X XFR Clothing (1)

a. Long-sleeve shirt X X X(9) Xb. Pants X(4) X(6) X(9) X

c. Coverall (5) (7) X(9) (5)

d. Jacket, parka, or rainwear AN AN AN AN

FR Protective Equipment

a. Flash suit jacket (multilayer) X

b. Flash suit pants (multilayer) X

c. Head protection1. Hard hat X X X X2. FR hard hat liner AR AR

d. Eye protection1. Safety glasses X X X AL AL AL

2. Safety goggles AL AL AL

e. Face and head area protection

1. Arc-rated face shield orhood

X(8)

2. Flash suit hood X X

3. Hearing protection (earcanalinserts)

X(8) X X

f. Hand protection

Leather gloves AN X X X

g. Foot protection

Leather work shoes AN X X XPPE Arc Flash Gear Required N/R N/R 4cal 8cal 25cal 40cal

Hazard categories up to 2 will require 11 calorie protection.Hazard categories over 2 will require 40 calorie protection.AN = As needed AR = As required AL= Select one in group X= Minimum required

Notes:(1) See Table 130.7 (C) (11). Arc rating for a garment is expressed in cal/cm

2.

(2) If voltage-rated gloves are required, the leather protectors worn external to the rubber gloves satisfy this requirement.(3) Hazard/Risk Category Number -1 is only defined if determined by Notes 3 or 6.(4) Regular weight (minimum 12oz/yd

2fabric weight), untreated, denim cotton blue jeans are acceptable in lieu of FR pants.

The FR pants used for Hazard/Risk Category 1 shall have a minimum arc rating of 11 cal.(5) Alternate is to use FR coveralls (minimum arc rating of 11 cal) instead of FR shirt and FR pants.(6) If the FR pants have a minimum arc rating of 11 cal, long pants of non-melting or untreated fiber are not required beneath

the FR pants.(7) Alternate is to use FR coveralls (minimum arc rating of 11 cal) over non-melting or untreated natural fiber pants and T-

shirt.(8) A face shield with a minimum arc rating of 11 cal, with wrap around guarding to protect no only the face, but also the

forehead, ears and neck is required.


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(9) Alternate is to use two sets of FR coveralls (the inner with a minimum arc rating of 4 cal and outer coverall with aminimum arc rating of 5) over non-melting or untreated natural fiber clothing, instead of FR coveralls over the FR shirt andFR pants over non-melting or untreated natural fiber clothing.


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Appendix G:Inspection Schedule for Rubber Insulating Equipment

Type of Equipment When to Test

Rubber insulating line hose Upon indication that insulating value is suspect

Rubber insulating covers Upon indication that insulating value is suspect

Rubber insulating blankets Before first issue and every 12 monthsthereafter (*)

Rubber insulating sleeves Before first issue and every 12 monthsthereafter (*)

Rubber insulating gloves Before first issue and every 6 months thereafter(*)

(*) If the insulating equipment has been electrically tested but not issued forservice, it may not be placed into service unless it has been electrically tested withinthe previous 12 months.

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Electrical and Arc